Oncotype DX May Not Be Necessary to Predict Recurrence in Low-Grade Breast Cancer

April 2014, Vol 5, No 3

San Diego, CA—Results of a new small study have shown that histology without the use of Oncotype DX Breast Cancer assay accurately predicts the risk for recurrence in low-grade breast carcinoma. Although Oncotype DX is useful in predicting recurrence in high-grade breast cancer, this study suggests that low-grade tumors may be adequately assessed for recurrence by histology only.

Two pathologists reviewed the clinical grade of breast tumors that also had been evaluated with an Oncotype DX assay, and found that in the 19 tumors that showed low-grade carcinoma on histology had an Oncotype DX recurrence score of ?30, which indicates low- or intermediate-risk for recurrence. Of those tumors, 17 (89.5%) had a recurrence score of <18, which corresponds to low recurrence risk.

Scott M. Wendroth, MD, Pathology Resident, and Kristen A. Atkins, MD, Associate Professor of Pathology, University of Virginia, Charlottesville, reported the results of their study at the 2014 United States and Canadian Academy of Pathology annual meeting. They hope to publish their results in the near future.

“The choice of sending a tumor for Oncotype DX analysis is still up to the patient and her treating clinician, and low-grade tumors continue to be occasionally sent for Oncotype DX at our institution,” said lead investigator Scott M. Wendroth, MD, University of Virginia, Charlottesville.

“Although our study was small, others have shown similar results, and we hope that these data are part of the discussion clinicians have with patients when deciding whether or not to use an expensive molecular test like Oncotype DX.”

A 2013 study that mirrors these results showed that routine histopathologic characteristics predict the Oncotype DX recurrence score in a subset of patients with breast cancer (Mattes MD, et al. Cancer Invest. 2013;31:604-606).

Dr Wendroth said that their next step is to continue monitoring the correlations between the recurrence scores of any low-grade breast cancers from their institution that are analyzed by Oncotype DX and the histology grade.

Dr Wendroth and Dr Atkins retrieved all low–Nottingham-grade tumors from their institutional archives that had also been evaluated with the Oncotype DX Breast Cancer assay. They were blinded to the recurrence scores while confirming their histo­logy-based grades.

Furthermore, they found that only 2 of the 19 low-grade tumors had a recurrence score of 18 to 30, a score that indicates low- to intermediate-risk, whereas the other 17 had a recurrence score of <18, which indicates low-risk.

Dr Wendroth and Dr Atkins concluded that because adjuvant chemotherapy only benefits patients with high recurrence score breast tumors, those who have a low- or intermediate-grade tumor on histology may not need a molecular analysis.

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